In general, a window apparatus for use in a variety of buildings is essentially comprised of a window, such as a balcony window or an entrance/exit window, and a frame to which the window is coupled in a sliding opening/closing manner. Such a window apparatus must fulfill requirements of high grade mechanical properties required to overcome the weight of glass and to achieve durability and weather ability against outside air.
Recently, various shapes of windows, such as e.g., system windows and anti-crime windows, have been developed and used. One example of the system windows is a vertical sliding type system window, which provides a building with upgraded appearance and functionality and is widely applied to relatively large scale windows, such as e.g., living room windows and balcony windows.
In a conventional window apparatus, a frame is provided with a rail groove, to which a window, such as a balcony window or an entrance/exit window, is coupled in a sliding opening/closing manner. The rail groove, however, may disadvantageously act as an obstacle that makes passage of person's feet uncomfortable or may cause persons' feet to be dangerously caught thereby. Moreover, in the case where the frame is installed at a balcony, impurities, such as dust, etc., may be easily accumulated in the rail groove and a cleaning operation to remove the impurities from the rail groove may be difficult. In particular, the frame installed at the balcony and the rail groove thereof are easily exposed to invasion of wind and rainwater, suffering from considerable deterioration in air tightness and drainage ability.
To solve the above described disadvantages, Korean Registered Patents No. 10-167124 and No. 10-439112 disclose rail concealed type window apparatuses having enhanced air tightness and drainage ability. However, the disclosed configurations have several problems in that complexity in the configuration of coupling a window, such as a balcony window or an entrance/exit window, to a rail groove of a frame makes it very difficult to separate the window from the rail groove, in that a rainwater drain means is not provided, which results in poor drainage ability, and in that a simple windshield structure is not sufficient to tightly intercept invasion of wind.